。
She's very worried about how he's doing.
Literal
She [topic-は] his [genitive-の] body [genitive-の] condition [object-を] very is-worrying.
体の具合 ('one's physical condition,' literally 'body's condition') is the everyday way to refer to someone's general health or how they're feeling. 具合 itself is broader — 'condition, state' — applied to bodies, machines, situations alike. Compare with the more clinical 容態, used specifically about an ill or injured person's medical state. The を on 具合 marks it as the object of 心配する (which takes its 'worried about' object directly with を, no preposition).